Mica glass-ceramics

T. Yamamoto et al., Application of Mica Glass-Ceramics as Gas-Sealing Materials for SOFC, in Proceedings of the Fourth International Symposium on Solid Oxide Fuel Cells (SOFC-IV), Vol. 95-1, pp. 245-253, The Electrochemical Society (1995). 

Mica glass-ceramic / SiC (Nicalon ) High imchtnabiliiy [45]... 

Compatibility of mica glass-ceramics as gas-sealing materials for SOFC. Denhi Kagaku, 64, 575-581. 

The electrostatic capacitor uses organic polymer, mica, glass, ceramic, and anodic oxide film... 

In Section 1.5.1, the crystallization of non-steady-state processes will be examined using mica glass-ceramics. The relationship between the observed non-steady-state time lag and phase separation will be demonstrated. The basic relationship between nucleation and microimmiscibility will be discussed in the following section. 

Fluorine ions have achieved great practical importance in the controlling of nucleation by phase separation. The development of mica glass-ceramics in particular must be addressed at this point. The initiation of phase separation... 

The microstructure of the mica glass-ceramic of the phlogopite-type demonstrates direct interlocking of the mica crystals after heat treatment at 950 C for 4 h. This morphology is described as a house-of-cards in Section 3.2.6. 

Beall (1971) determined that different microstructures can be produced, depending on the composition crystallization process used. Furthermore, the chemical stability of the respective glass-ceramics also changes. The machin-ability of this mica glass-ceramic proved to be very favorable. A ceramic containing one-third by volume mica was shown to demonstrate satisfactory machinability. Optimum machinability was obtained at two-thirds by volume. 

A fluorine mica glass-ceramic with a mica phase containing Au ions, was developed in Japan. In addition, Zr02 crystals were formed in this glass-ceramic (Sumikin Photon Ceramic Co., 1998). The properties and applications of this material are discussed in Section 4.1.3. The trade name of this glass-ceramic is Fotovel . 

A dense microstructure of mica crystals formed in the glass matrix on heat treatment of625°C for 4 h and 1100°C for 6 h. The determination of the properties of this type of alkaline-fi ee mica glass-ceramics was of particular interest. 

Various investigations have been conducted in an effort to combine two specific properties in the fluorosilicate glass-ceramic system and in the mica glass-ceramic system in particular, that is, high strength and machinability as a result of mica precipitation. 

In the course of his comprehensive research on mica glass-ceramics, Beall (1991) examined a similar glass formation system, that is, Si02-Mg0-Ca0-R(I)20-F, where R(I)20 represents the alkali oxides Na20 and K2O. Small amounts of AI2O2, P2 5 2 added. 

From a materials development point of view, this special appearance of the mica crystals of phlogo-pite are of great interest. A detailed discussion of this topic will follow in Section 3.2.7. At the same time, however, it must be stressed that new or improved properties compared with mica glass-ceramics with plane or petal-shaped crystals result from the new, curved mica crystals. 

To sum up, the formation of the house-of-cards microstructure in mica glass-ceramics is characterized by the following solid-state reactions, which take place as consecutive reactions ... 

Figure 4-39 Flexural strength of pressed glass-ceramic IPS EMPRESS 2 in comparison to other dental materials, natural tooth, and technical ceramics (Kappert 1998). a) ISO limit, b) tooth enamei, c) tooth dentin, d), e) ieucite-based ceramics, f) iPS EMPRESS , g) feldspar ceramic, h) mica glass-ceramic, i) sintered spinei and infiltrated glass, j) sintered AlgOg and infiltrated glass, k) IPS EMPRESS 2,1) dense sintered AI2O3.

BUrke H., Durschang B., Meinhardt J., and Muller G., "Nucleation and Crystal Growth Kinetics in the Zr02-Strengthened Mica Glass-Ceramic for Dental Application," Glastech Ber. Glass Set. Technol, 73 [Cl] 270-77 (1971). 

Hoda S.N. and Beall G.H., "Alkaline Earth Mica Glass-Ceramics" pp. 287-300 in Advances in Ceramics, Vol. 4, Nucleation and Crystallization in Glasses. Edited by J.H. Simmons, D.R. Uhlmann, and G.H. Beall. American Ceramic Society, Columbus, OH, 1982. 

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